Regarding producing the copper alloy material for the copper alloy wire rod or for the copper alloy sheet material, at first, there is known the following process as the most common process (A) for a melting technology. First, a copper raw material, a scrap, and an additional element or a master alloy solid matter containing thereof are thrown into a melting furnace (an electric furnace, a gas furnace), and then a dissolution is performed therefor. Next, after melting all the substances in the furnace inside, a sample for analysis is collected from the inside of the furnace, a component and a concentration are measured and confirmed by using a chemical analysis or an instrumental analysis, and then a quality governing therefor is performed. Next, a slab, a billet, or the like, is cast by using a water cooled casting after confirming the predetermined component and the concentration, and then the wire rod or the sheet material becomes to be manufactured by performing re-heating such an ingot which is cooled once to a room temperature, and by performing a hot rolling and an extrusion therefor.
And regarding the above mentioned melting process, generally an induction heating process is adopted, and it is well known that an energy efficiency thereof is not good.
Next, there is known a series casting by using a belt and wheel type for such as an SCR or the like as another technology (refer to a patent document 1 for example), and it is the method as a lower processing cost thereby comparing to that according to the billet casting. Here, in such the process, a casting is performed for obtaining a predetermined alloy composition by throwing an additional element into between a melting furnace and a casting machine. It is desirable to perform a series dissolution casting for reducing a processing cost, however, a duration for series casting becomes shorter in a case where a dissolution capacity is inferior to a casting capacity. And then a processing cost rather becomes higher due to becoming a fraction defective thereof to be higher, because a proportion of the defective becomes to be relatively larger at a time of starting and stopping therefor. Hence, it becomes required an installation of a larger melting furnace for corresponding to the casting capacity thereof, and then an initial investment in plant and equipment becomes to be a huge amount thereof. Thus, it is desirable to develop a melting equipment having an equivalent capacity to the casting capacity with less investment in plant and equipment. On the contrary, according to the technology disclosed in the patent document 1, the energy efficiency is high due to making use of a shaft kiln exclusively as the melting furnace. However, according to such the process, only a dilute copper alloy may be dissolved thereby (it is able to provide as an example a Cu-0.7% Sn alloy as the highest concentration or the like).
Therefore, there is known a process (B), wherein an additional element or a master alloy solid matter containing thereof is directly thrown into a flowing molten copper and then a component is prepared by the series dissolution of the additional element, or a molten metal storage part is provided at a part where the molten metal passes therethrough, which comprises a heating part, and then an alloying element is added and mixed thereinto. Moreover, there is known a process (C) (refer to a patent document 2, 3 and 4 for example), wherein a molten metal is added directly at a transferring process of a molten metal at a period of a series casting therefor and then a preparation of a component is performed therefor. According to such the process: a heater is arranged directly onto a tundish of a series casting therefor, which drives out the alloying element as to be a semi-molten state or a molten state, the alloying element is dripped into a molten metal in the tundish inside and stirred, and then a homogeneous molten metal is obtained (the patent document 2); a molten copper is accommodated in a tundish inside and a Ni and a P are added as a form of a Ni—P compound into such the molten copper in the tundish inside (the patent document 3); a wire rod comprised of an additive alloy component is continuously melted or semi-molten by using an arc discharge, or the above mentioned additive alloy component to be melted or to be semi-molten is added into a molten metal of a basic metal component to be fluidized, and then a molten metal is obtained in which the above mentioned additive alloy component is melted (the patent document 4).
Further, as a process for performing a component preparation at a period of series casting, there is known a process (D) (refer to a patent document 5 for example), wherein an electric conductivity of a rough drawing wire to be processed by using a series casting and rolling is measured continuously, and then a dosage of the alloying element is continuously controlled by performing a feed back of such the result therefor.
However, there is only an alloy of simple solid solution hardening type which is put to practical use. And, it is impossible to perform a component assay according to the electric conductivity of the rough drawing wire, because the electric conductivity thereof is varied with depending on a precipitation state at a period of a hot rolling therefor regarding an alloy of precipitation type, such as a Cu—Ni—Si base or the like.
Still further, there is already known regarding the measurement of the resistance of a molten metal by energizing with electricity therethrough. For example, each of the specific resistance values of the pure metals are shown in “Metal Data Book” edited by Japan Society of Mechanical Engineers, and the values are larger than the specific resistance values at a room temperature therefor respectively (refer to Table 1). However, regarding the copper alloy, the Corson alloy in particular, the resistance of the molten state therefor has not known yet. It may be considered that it becomes possible to control thereof somehow if it becomes cleared regarding a relationship between a component of such the alloyed and the specific resistance at the molten state thereof, however, it has not realized yet.
TABLE 1Comparison of specific resistancesSOLIDMELTMELTINGTEMPERATURESPECIFICTEMPERATURESPECIFICPOINTELEMENT(° C.)RESISTANCE(° C.)RESISTANCE(° C.)Cu201.67110020.21083Ni206.84145485.01453Si202.3 × 1010141082.0—Unit of specific resistance: μΩcm
Furthermore, as a process to be paid attention to an electrical characteristic of such the molten metal and to be made use of an assay of the properties regarding the molten metal, there is known a process (E) for detecting an inclusion in the molten metal (in the aluminum alloy in particular) (refer to a patent document 6 for example). According to such the process, an amount of a reduction due to the inclusion regarding a cross section of an electric current path is monitored, wherein the electric current in the electric current path inside is assumed to be as between one and 500 A, an electrical resistance thereof in the path inside is measured continuously, and then a variation of an electric signal is measured at a period when the inclusion particle passes through the electric current path inside. However, it is not for detecting a variation of a resistance value according to a variation in concentration of the molten metal in the electric current path inside.
[Patent Document 1] Japanese Patent Application Publication No. Shou 55-128353 (1980-128353)
[Patent Document 2] Japanese Patent Application Publication No. Shou 59-169654 (1984-169654)
[Patent Document 3] Japanese Patent Application Publication No. Hei 8-300119 (1996-300119)
[Patent Document 4] Japanese Patent Application Publication No. 2002-086251
[Patent Document 5] Japanese Patent Application Publication No. Shou 58-065554 (1983-065554)
[Patent Document 6] Japanese Patent Application Publication No. Shou 59-171834 (1984-171834)